Grinding-wheel dressing attachment



Aug. 3 1926. 1,594,393

P. F. VOKAL GRINDING WHEEL DRESSING ATTACHMENT Filed July 24 1 24 2 Sheets-Sheet 1 A TTORNEV Aug; 5:33 9 15 326. 1,594,393

P. F. VOKAL v GRINDING WHEEL DRESSING ATTACHMENT Filed July 24. 24 2 Sheets-Sheet 2 is Z ATTORNEY Patented Aug. 3, 1926.

UNIT-ED STATES PATENT OFFICE.

VOKAL, 01B KABTFOBD, COMPANY, 01 NEW YORK,

tenor. r.

CONNECTICUT, ASSIGNOB T PRATT 8n WHITNEY N. Y., A CORPORATION OF NEW JERSEY.

GRINDING-WHEEL DRESSING ATTACHMENT.

Application fled July 24,

4 rality of grinding ridges on a thread grinding wheel in a new ner.

Another object of my invention is to provide a method of dressing. a thread grinding wheel that shall true a number of grinding and an improved manridges on the wheel in an eificient manner.

A single that one grin In grinding many threaded articles, such for example as taps, it has been customary heretofore to grind the threads by means of a grinding wheel having a single grinding ridge. When a grinding wheel having a single grinding ridge is used for grinding a tap, it is necessary to rotate the tap as many times during the grinding operation as the number of turns of thread. Thus, in a thread of small pitch, the grinding operation extends for a considerable length of time. In a grinding machine having a whee dressed in accordance with my invention a grinding wheel is provided with a plurality of The time of the grinding operation, whee having a number oi? ridges, is cut down in accordance with the number of grinding ridges on the wheel. It should also be noted ding wheel will grind a number of threads having or eaamplaif the grinding a quarter of an inch apart, it is possible to grind any thread having an even multiple of our threads per inch. Y

In a grinding attachment constructed in accordance with my invention, it is possible to true a number of grinding ridges on a grinding wheel in an eilicient manner so as to out threads having an exact angle and a uniform lead.

in the accompanying drawings:

Figure l is a plan view of a thread grinding machine provided with my truing attachment.

Figs. 2 and 3-.are respectively plan and side elevational views of a dressing bar tor cutting fillets between the grinding ridges of the wheel.

Fig. 4: is an en arged plan view. of my dressing attachment.

.1924. Serial No. 727,829.

Fi 5 is a side elevational view of the attac ment shown in Fig. 4. I

Fig. 6 is an end view of the attachment shown in Fig. 4.

Figs. 7 an 8 are respectively side elevational and and views of the dressing bar for truing the sides of the grinding ridges.

F1 9 is an enlarged view showing a grin mg wheel in engagement with a tap.

Fig. 10 is a diagrammatic view showing the angular relation of the wheel axis to the "blank axis.-

Referring to the drawings and particularly to Fig. 1, a headstock 1 and a tailstock 2 are shown mounted on a carriage 3 he work piece, which in the machine under consideration is a tap, is secured between the centers of the head and tailstock. A grinding wheel 4- is mounted on a shaft 5. The shaft 5 is carried in any suitable manner 6. Adjacent upon a wheel slide ing wheel 4 and carried by the slide 6 is a dressing slide 7. Thedressing slide 7 carwill be deries a dressing plate 8 which hereinafter. hand scribed more fully effecting movement wheel 9 is provided for not only of the wheel slide 6 but also of the dressing slide 7 when a dressing operation is being performed. The hand wheel 9 moves the wheel slide 6 twice the distance through which the dressing slide 7 is moved in order to maintain the grinding wheel 4. in correct relation with respect to the work. The plate 8 is mounted on the slide 7 in a plane parallel to the axis of the blank being operated on. The shaft 5, of the wheel 4 1s set at an angle to the blank axis in accordance with the helix angle of: the thread on the blank. The gearing connection etween the two slides is fully described and illustrated in the companion application of Carl Schramm and an F Vokal, Serial No. 717 ,794, filed June 4. 1924. p

The carria e 3, which supports the headstock 1 and t e tailstock 2, is moved longitudinally in timed relation to the rotation of the headstockspindle. A tall description of the gearing connection for operating the carriage and headstock spindle is set forth in the above mentioned application of Schramm et al. and accordingly a detailed description in this application is 'deemed unnecessary. may be noted, however,

for adjusting a hand wheel T0 is provided to the grindthat -: in operation.

the position of the carriage 3 on the main frame of the machine and a hand wheel 11 is provided for adjusting the position of the wheel slide The grinding wheelv 4 is grinding ridges numbered 12 to 17, sive. Each to grind the thread of a tap. The ridges have the same shape and are evenly spaced apart so that each grinding ridge engages a certain part of the thread on the tap when Referring to Fig. 9 of the drawings, it will be noted one turn of the thread is disposed between each pair of grinding ridges. Accordingly, it would take only two complete turns of the ag to grind the complete thread. If the grin ing wheel were only provided with one grinding ridge, it is apparent the tap would have to rotated as many times as the turns of the thread in order to completely grind such thread.

The grinding not restricted to provided with six incluwheel under discussion is one pitch but may be used of different pitch. if the grinding ridges are disposed exactly a quarter of an inch apart, it is apparent such grinding wheel will grind a tap having four threads, eight threads, twelve threads,

or any multiple of four threads per inch.

Accordingly, it is apparent only limited number of grin quired for The plate 8, which is secured to the dressing slide 7, is provided with two sets of guiding grooves 18 and a very ding wheels are responds to the pitch of the thread which is e work piece. If the wheel are separated in grinding a formed on th grinding ridges on the of an inch,

a multiple of three threads per inch, the grinding ridges on the grinding wheel will be loca d a third of an inch ves in the the ridges the grinding wheel 4. The set 18 serve to true one side of of the grinding ridges is shaped 17 ,of the grinding ridges. T

grinding all the taps of usual size. f

19. The sets of l a quarter b surfaces the set 19 serve to true ridges. A groove 22 is formed in the plate 8 pa'rallel to the axis of the grinding Wheel. Such groove 22 serves to guide the dressing bar 21 for truing the peripheral edge of each of the ridges 12 to inclusive.

The dressing bar 21, as illustrated in Figs. 7 and 8, of the drawings, is provided with two cutting points 23 and 24. The point 24 is used for dressing the side surfaces of the ridges 12 to 17, inclusive, and the cutting point 23 is used to dress the eripheral edges e dressing bar and the grooves in the other side of the grooves in the sets of grooves 18 and 19 and the groove 22. During the dressing of the peripheral edges of the grinding ridges by the cutting point 23, the

the angular t0 the Wheel angle as heretofore set betweensuch axes,

helix angle of the orth, corresponds to the blank thread. The dressing bar 21 trues the grinding ridges of the Wheel'4 on a line he axis of the blank.

ground.

which is illustrated in cutting point 24 to a dressing tool 28 is point 31 mounted which as not to engage-the side of the ridges when the fillets are being formed in the Wheel.

In ressing a grinding wheel in accord ance with my invention, the fillets 30 are first formed in the wheel be ween the grinding edges by means of the ressing bar 28. If so desired, the bar may be rested upon the axis b b is illustrated. The

on an end portion 32 drawings," is provided ,bysaid grooves for elusive, are dressed by means of thecutting i ,the dressing bar 21 being guided by i .s of grooves 18 and 19 as before de- Al though I have illustrated-my invention by a grinding wheel composed of but six grinding ridges, it is to be understood that the grinding wheel may be provided with any desired number of such ridges. Moreover, the spacing of the ridges and the shape thereof may be varied in accordance with the threads being ground.

Modifications in the attachment and in the arrangement and location of parts may be made within the spirit and scope of my invention and such modifications are intended to be covered by the appended claims.

What ll claim is:

1. In a dressing attachment for the wheel of a thread grinding machine, the combination comprising a plate having two sets of guide grooves formed therein, the sets of said grooves making an angle with each other corresponding to the angle of the thread being ground, and a dressing bar guided by said grooves for dressing the sides of a plurality of grinding ridges on the grinding wheel.

2. In a dressing attachment for the wheel of a thread grinding machine, the combination comprising a plate having two sets of guide grooves formed therein, the sets of said grooves malring to the angle of the thread being ground, guided by said grooves for dressing the sides of a plurality of grinding ridges on the grinding wheel, said plate having a groove parallel to the axis of the grind-.

to dressthe ing wheel for guiding said bar periphery of the ridges on the wheel.

3. lin a dressing attachment for the wheel of a thread grinding machine, the combination comprising a plate having two sets of guide grooves formed therein, the sets of said grooves making an angle with each other corresponding to the angle of the thread being ground, a dressing bar guided by said grooves for dressing the sides of a plurality of grinding ridges on the grinding wheel, and a second dressing bar for forming an enlarged fillet between the ridges formed on the wheel, said plate being set at an angleto the axis of the wheel during the dressing operation.

i. In a dressing attachment for the wheel of a thread grinding machine, the combination comprising. a plate having two sets of guide grooves formed therein, the sets of said grooves malring other eorrespondlng to thread being ground, a

an angle with each the an le of the dressing ar guided dressing the sides of an angle with each and a dressing bar said grooves vof'each ridge, ,saidj late' having a groove a plurality of grindin ing wheel, said plate allel to the axis of the grinding wheel for guiding said bar to dress the periphery of the wheel, and a second dressing bar for forming an enlarged fillet between the ridges formed on the whee v 5. In a dressing attachment for a thread grinding wheel having a plurality of one nular grinding ridges, the combination comprising a guide plate having two sets of guide grooves formed therein, the sets of grooves making an angle with each other corresponding to the angle of the thread ridges on the grind- .being ground and the grooves of each set being spaced apart a distance corresponding to the pitch of the thread being ground, and a dressing bar guided by one set of said grooves for dressing one side of each of said ridges and guided by the opposite set of said grooves for dressing the opposite side of each ridge.

6. In a dressing attachment for a. thread grinding wheel having a plurality of annular grinding ridges, the combination comprising a guide'plate having two sets of guide grooves formed therein, the sets of grooves making an angle with each other corresponding to the angle of the thread being ground and the grooves of each set be ing spaced apart a distance corresponding to the pitchof the thread being ground.

grooves fpr dressingone side of each of said ridges and guided by the opposite set of for dressing the opposite side a dressing bar guided'bv one set of said parallel to the axisi of thegrinding wheei for guiding said bar todress the periphery of the rid es. 7

-7. Ina ressingnattachmentjfor a thread grinding wheelhaving a plurality of an. nular grinding ridgeathe combination comprising a guide platehaving two sets 0a guide grooves ormed therein, the sets oi grooves making an angle with each other corresponding to the angle of the thread being ground and the grooves of each set being spaced apart a distance corresponding to the pitch of the thread beingground, dressing bar guided by one set of said grooves for dressing one side of each of said ridges and guided by the opposite set of said grooves for side of each ridge, said plate having a groove parallel to the axis of the grinding wh for guiding said bar to dress the periphery of the grooves, and means comprising a slide for moving the plate perpendicularly with respect to the axis of the wheel.

In testimony whereof, I hereto ailix my signature.

PAUL F. VUKAL.

aving a groove par- 00 dressing the opposite 

